SN95 Pedal Box

[twatson799]

217245After trying nearly everything to keep the brake switch from constantly lighting the brake lights, I concluded that the resting position of the post on the brake pedal is too close to the master cylinder. It seemed like the rod going into the hydrobooster was always under compression. I moved the whole pedal box away from the front wall of the foot box by two washers. This solved the brake switch issue. However, have I created any new issues by spacing it out this way? Should I build a plate the full size of the face of the pedal box instead or am I ok?

[Jim Doak]

Do you have a slight gap between the push rod from your brake pedal to where it contacts the master cylinder? If not, perhaps there's a small amount of pressure forcing the rod against the brake pedal, triggering the switch.

If I remember correctly, the gap between the end of the rod to where it contacts the master cylinder should be around 1/16" or so. (You'll need to do a quick Web search to verify the actual value.) There's an inexpensive H-shaped tool to measure the gap.

Edit: I found the following after a quick Web search. Perhaps you already aware, but if not...

"Hydroboost rod adjustment is crucial for proper brake function, ensuring the master cylinder is engaged correctly and avoiding issues like excessive free play or premature braking. The rod's length is adjusted by loosening a lock nut, turning the rod to achieve the correct distance, and then tightening the nut to secure the adjustment. A small gap, typically around 0.020 inches or 1/16 inch, between the booster pushrod and the master cylinder is generally desired to allow for free play before the brakes engage."

Regarding the spacers: I'm also using an SN95 pedal box and removed the factory spacers as described in the Base Kit manual. But since Ford spaced out the hydroboost unit from the firewall in the Mustang, I don't see a problem with your washer fix.

[twatson799]

Thanks for the tips. I didn’t realize the Hydroboost rod length was adjustable. I think I will leave it be for the moment. If I have to remove the bolts for some other reason, I will try to adjust the rod and remove the washers.